Speed control for motors



Dec. 30, 1952 A. w. HOLSTEIN 2,623,962

SPEED CONTROL FOR MOTORS Filed Aug. 1:5, 1949 PatentedDeaIiO, 1 2 I 2,623,962

UNITED STATES PATENT .oFFlc 2,823,862 srssn comor. ron morons Alvin W. Holstein, St. Louis, Mo., allignor to Knapp-Monarch Company, St. Louis, Mo a corporation of Delaware Application August 13, 1949, Serial No. 110,155

1 2 Claims. (Cl. 20H.)

This invention relates to a speed control of My speed control comprises a circuit breaker centrifugal type for motors of the series-wound having a spring contact blade 2| and a contact fractional horsepower type such as those used it. A spring blade ll mounted on asupporting for food mixes and other food processing aparm 34 by means of a screw it constitutes a paratus, mounting spring for a switch base 32 on which One object of the invention is to provide a the blade 28 and the contact II are mounted. speed control device of the contact breaker type The supporting arm 34 extends from a large which has a novel adjusting arrangement wherewasher 38 mounted on a plurality of studs 4| in the adjusting knob may form a continuation and biased toward the frame 28 by springs 42. A of the housing for the motor and speed control somewhat smaller washer'44 serves as a mountdevice. a ing for the extension housing l2 which is secured Another object is to provide a speed controller to the washer 44 by screws 48, positioning studs which is particularly adapted for mounting at the 48 being provided on the extension housing l2 end of the motor shaft in an extension housing to enter openings ll of the washer 44. of the motor housing, and an adjusting means The extension housing l2 houses the contacts for the speed controller is provided which may 28 and and a pair of spiders I2 and '54. The form a further continuation of the housing spider 52 is secured to the shaft 24 by a collar II A further object is to provide an adjusting and the spider 54 carries an insulating button it screw mechanism for the speed controller or adapted for actuating the switch 22-". governor which includes a slidable and not rotat- The spiders 52 and 54 are riveted together at able screw on which an adjusting knob is threadthe outer ends of their arms as indicated at It ed, and the knob is held against end-wise moveand these rivets serve as centrifugal weights in a ment while permitted to rotate so that rotation manner which will hereinafter be disclosed. of the knob will adjust the screw in a direction The switch 28-3. constitutes a flutter relay for axially of the motor and thereby position a concontrolling the mo r whic is hown di ramtactbreaker closer to or farther away from cenmatically at M in Figure 1. The switch is in trifugally operated spiders that control the posiseries with the motor and is shunted by a contion of the contacts. denser 62 for reducing arcing at the contacts With these and other objects in view, my inand a resistor 64 for partially s e 0! fully vention consists in the construction, arrange- 30 energizi the m o M when he contacts are ment and combination of the various parts of my Openspeed control for motors, whereby the objects Speed controllers of the centrifugal contact contemplated are attained, as hereinafter more breaker type disclosed may be used to adjust the fully set forth pointed out in my claims and illus- J speed of the motor by moving the switch base 32 trated in the accompanying drawings, wherein: closer toaor farther away from the end of the Figure 1 is a sectional view through a motor motor shaft 24. Figure 1 shows an adjustment for and its housing showing my speed control slow speed and Figure 2 an adjustment for high mounted in an extension of the housing and the speed. For the purpose of such adjustment, the adjusting means therefor in section. spring blade 85 biases the base 32 to engage an Figure 2 is a repetition of a portion of Figure 1 adjusting screw 66 which is slidably and nonshowing the parts adjusted to a different posirotatably mounted relative to the washer 44 by tion; means of a tongue is bent from the washer and Figure 3 is an end elevation of the centrifugalextending into an axial slot III of the screw. ly-operated spiders; and The screw is then adjusted axially by means of a Figureis an enlarged detail sectional view on 4 nut 12 rotatable in a hub 14 of the extension the line 4-4 of Figure 1. housing [2 but non-slidable therein by being On the accompanying drawing I have used the limited against end-play by retainer washers 16 reference numeral III to indicate a motor housand 18. A cupped spring washer 80 is interposed ing, I2 an extension thereof, [4 the field of the between the retainer washer l8 and the hub I4 to motor and IS the armature thereof. The field retain the nut 12 in any position to which it is adwindings are illustrated in a general way at is justed.

and the armature winding at 20. A self-aligning An adjusting knob 82 is mounted on the nut bearing 22 is provided for the motor shaft 24 and 12 as by a set screw 84 and serves as a means to it is held in a part of the motor frame or housing manually rotate the screw for adjusting purposes 10 indicated at 26 and shown in section. in an obvious manner. The sub-housing [2 may I until the speed reaches the predetermined speed to which the controller has been adjusted. At'

such speed the centrifugal force on the spiders 52 and 54 is such as to collapse them sufficiently for separating the contact blade 28 from the contact 30 thereby momentarily throwing the resistor 64 in circuit with the motor M. This slows down the motor and the contacts will reclose with alternate opening and closing to maintain the desired speed of the motor in a hunting manner but when the parts ar properly designed the contact blade 28 merely flutters against the contact 30 and there is no noticeable change in the speed of the motor due to the governor action.

I have provided a conveniently accessible adjusting knob for controlling the position of the switch base 32 and thereby the speed of the motor and the parts therefor are comparatively simple andinexpensive to manufacture and assemble.

Some changes may be made in the construction and arrangement of the parts of my speed control for motors without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim as my invention:

1. In a speed control for motors, a switch base at the end of the motor shaft, a normally open switch mounted thereon, said switch base being biased away from the motor shaft, centrifugally operated spiders carried by the motor shaft and having a switch engaging element normally extended away from the motor shaft for causing engagement of the contacts of said switch, said spiders collapsing in a direction axially of and toward the motor shaft upon increase in speed of the motor for thereby permitting said switch to open, and means for adjusting said switch base comprising a threaded rod against which the switch base is biased, said rod being slidably and non-rotatably carried at the end of the motor shaft, a knob threaded on said rod and means for mounting said knob for rotation and against axial movement.

2. In a speed control for motors, a switch base at the end of the motor shaft, a normally open switch mounted thereon, said switch base being biased away from the motor shaft. centrifugallyoperated spiders carried by the motor shaft with the inner one secured thereto and the outer one beyond the motor shaft and normally causing engagement of the contacts of said switch, said spiders collapsing in a direction axially of and toward the motor shaft upon increase in speed of the motor, and means for adjusting said switch base comprising a frame resiliently connected with the motor, an extension motor housing secured to said frame, a thrust rod slidable in said extension motor housing and against which said switch base is biased, and a knob having threaded engagement with said thrust rod, said knob being rotatably carried by said extension motor housing for rotation only relative thereto.

f ALVI N w. HOLSTEIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,795,240 Ulmer Mar. 3, 1931 2,493,897 Petz Jan. 10, 1950 

